1. Field of the Invention
The present invention relates to signal processing, and, in particular, to packet formats used to transmit messages between different components in a telecommunication system.
2. Description of the Related Art
FIG. 1 shows a block diagram of a portion of a prior art telecommunication system 100. In particular, FIG. 1 shows a central office (CO) 102 of system 100 configured to a remote terminal 104 via a high-bandwidth (e.g., T1) link 106. Remote terminal 104, which conforms to the AnyMedia Access System(trademark) (AMAS) specification of Lucent Technologies of Murray Hill, N.J., comprises a controller 108 and a plurality of peripheral packs 110. Each peripheral pack 110 supports telecommunication services for a number of (e.g., up to 32) different of end users (e.g., ordinary telephones (not shown) connected to remote terminal 104 via conventional TIP/RING phone lines 112). Controller 108 provides the communication interface with CO 102 for remote terminal 104 and controls the operations of the different peripheral packs 110. In particular, controller 108 receives status information from the individual peripheral packs 110 (e.g., information regarding the state of the individual supported phone lines and/or information regarding the peripheral pack itself) via internal point-to-point communication links 114 within remote terminal 104. In addition, based on instructions received from CO 102 and/or based on its own internal processing of the peripheral pack status information, controller 108 generates and transmits commands for configuring individual peripheral packs 110 via the corresponding point-to-point links 114.
Table 1 defines the 6-byte Access Interface Unit (AIU) Message Format used for point-to-point communications between the controller and the individual peripheral packs within a remote terminal that conforms to the Lucent AMAS specification, such as remote terminal 104 of FIG. 1. The AIU Message Format in Table 1 supports message packets from 3 to 6 bytes long. Bits B0-B1 of Byte #0 define the length of the message format by indicating the number of data bytes present, where binary value (B1 B0)=(00) indicates a 3-byte packet with one data byte, (01) indicates a 4-byte packet with two data bytes, (10) indicates a 5-byte packet with three data bytes, and (11) indicates a 6-byte packet with four data bytes. Bytes #0-2 are present in every packet, with the presence of Data Bytes 3-5 being dependent on the length of the packet. Bits B2-B7 of Byte #0 are used for parity bits that ensure the security of packet transmission, where each parity bit corresponds to the even parity value of a different one of the bytes in a packet. Bits B2-B7 of Byte #1 define the job type (e.g., on-hook, off-hook), which determines the meaning of, and actions to be taken upon receipt of the data. Bytes #2-5 are data bytes containing data for the specified job type. Bits B0-B1 of Byte #1 are undefined.
As described, the AIU Message Format of Table 1 was designed to support point-to-point communications between the controller of a remote terminal that conforms to the Lucent AMAS specification, such as controller 108 of FIG. 1, and the individual co-located peripheral packs, such as peripheral packs 110. It would be desirable, however, to provide communication systems with configurations other than that shown in FIG. 1. Unfortunately, the AIU Message Format of Table 1 is limited in the types of system configurations that it can support.
The present invention is directed to an extended messaging scheme based on the 6-byte AIU Message Format of Table 1 that supports multi-packet messaging over a variety of telecommunication system configurations. In one embodiment, the extended messaging scheme provides three additional 6-byte packet formats, corresponding to (1) initial packets (called xe2x80x9cfirst-of-manyxe2x80x9d packets) for messages requiring more than one 6-byte data packet, (2) subsequent packets (called xe2x80x9ccontinuationxe2x80x9d packets) for those multi-packet messages, and (3) sole packets (called xe2x80x9cfirst-and-onlyxe2x80x9d packets) for messages requiring only a single data packet.
In one embodiment, the present invention is a component for a telecommunication system, comprising (a) an input/output (I/O) port configured to receive and transmit data packets over a point-to-point communication link of the telecommunication system; and (b) a processor configured to the I/O port to process data packets received over the communication link and to generate data packets for transmission over the communication link. The processor supports data packets conforming to the AIU Message Format of Table 1 as well as one or more additional packet formats comprising (1) a first-packet format corresponding to an initial packet of a single message, wherein the single message is transmitted over the point-to-point communication link as one or more data packets; and (2) a continuation-packet format corresponding to an other-than-initial packet of the single message for single messages transmitted over the point-to-point communication link as two or more data packets.
In another embodiment, the present invention is a telecommunication system, comprising (a) a remote terminal and (b) at least one client terminal. The remote terminal comprises (1) a remote terminal controller; and (2) one or more packs, each configured to communicate with the remote terminal controller via a point-to-point communication link, wherein the one or more packs comprise zero, one, or more peripheral packs and one or more server packs. Each client terminal comprises (1) a client terminal controller configured to communicate with a corresponding server pack of the remote terminal; and (2) one or more client packs, each configured to communicate with the client terminal controller via a point-to-point communication link, wherein the one or more client packs comprise zero, one, or more peripheral packs and zero, one, or more server packs. The remote terminal controller, the at least one client terminal controller, and the one or more server packs support data packets conforming to the AIU Message Format of Table 1 as well as one or more additional packet formats comprising (1) a first-packet format corresponding to an initial packet of a single message, wherein the single message is transmitted over the point-to-point communication link as one or more data packets; and (2) a continuation-packet format corresponding to an other-than-initial packet of the single message for single messages transmitted over the point-to-point communication link as two or more data packets.